1. Field of the Invention
This invention relates to a curtain attachment connector that enables various curtains for home and institutional uses, such as theaters and hospitals, to be easily attached to or removed from the suspending materials of curtain railings and curtain holders. More specifically, this invention relates to a curtain attachment connector in which pleats are formed automatically at the top end of the curtain, at the time the curtain is attached to the railings, thereby eliminating the process to provide gatherings to the curtain, and at the same time horizontal opposite ends of the curtain are firmly attached so that the ends are protected even when the curtain is opened or closed by being pulled quickly and strongly.
2. Description of the Related Art
The top end of a curtain to be suspended from the railing normally has gatherings, partly to emphasize the physical beauty of the appearance of the curtain when opened or closed arid partly to prevent the bottom end of the curtain from parting when the curtain is closed. Providing gatherings to the curtain requires complex work of skilled hands and is time-consuming, adversely affecting production costs. By adopting conventional gathering technique, it influences the production cost, so that depending on the uses of the curtain, the gathering process is sometimes omitted for productivity reasons. But curtain without gatherings has lower commercial value and lesser satisfaction to customers.
On the other hand, most of the curtains used at hotels and hospitals are on lease, requiring volume distribution and frequent change and laundering. Therefore, it is desirable to have the curtain structure that is both cost and time efficient at the time of changing and laundering, on the one hand, and that enables automatic pleating at the time of attaching the curtain to the railing and the pleats disappear when curtain is removed from the railing, on the other.
To meet such market needs, U.S. Pat. No. 5,012,552 or of U.S. Pat. No. 5,109,912, for instance, describes a connector in a plate form comprising woven knitted surface fastener adhered to both sides thereof curtain. Those U.S. Patents disclose the ways the surface fastener is pressed onto the corresponding surface fastener adhered to the upper end of the curtain, thus forming pleats and at the same time putting the connector's curtain runners through a curtain railing to attach the curtain. The curtain could be attached to the connector by lightly pressing the surface fastener on the curtain to the corresponding surface fastener on the connector, while the curtain can be removed from the connector by simply separating the two surface fasteners, according to those U.S. Patents.
The curtain connector disclosed in those U.S. Patents, however, does not address the relative strength of engaging of the two surface fasteners. An example described in U.S. Pat. No. 5,012,552, for instance, shows a curtain connector one side of which is a hook surface fastener and the other side is a loop surface fastener, but also indicates that both sides may be of the same engaging structure. As is clear from such description, the attaching of the curtain connector to the curtain is achieved by associating a hook surface fastener to loop surface fastener or vice versa, using the usual woven/knitted surface fasteners, and the engaging strength (tearing strength) on both sides of the curtain connector are equal. Also, the curtain connector described in U.S. Pat. No. 5,109,912 apparently has the surface fasteners with the same engaging strength on both sides thereof as shown in its embodiment.
The curtain connectors as above are generally designed to have the strength to withhold both the weight of the curtain itself and downward pull at the time of opening and closing the curtain. In the case of the curtain connector disclosed in the aforementioned U.S. Patents, the curtain is supported by both sides of the curtain connector. Therefore, the engaging strength in either side of the connector could be set lower than that of a single-face conventional connector. When the total engaging strength is set to correspond to the normal curtain-support strength, however, the engaging strength on either side of the curtain connector is not strong enough to withhold a temporary downward pull at the time of opening and closing of the curtain, and the curtain might come off locally. Conversely, when the engaging strength on both sides of the curtain connector is increased simultaneously, the curtain does not come off the connector easily. However, the impact of the downward pull on the curtain directly works on the curtain connector, thus deforming or damaging the resiliently vulnerable portion of synthetic resin that connects the connector to the curtain railing. The end result is that the curtain comes off, just as in the case of inadequate engaging strength on the connector and that the curtain connector should be replaced before its life expires.
The curtain connector disclosed in the U.S. Patents mentioned above uses regular surface fastener woven or knitted of fabrics as the surface fasteners on both sides, thereby creating no specific manufacturing problems in, for instance, forming hooks in the conventional method. When the surface fasteners are manufactured by integrally molding fastener surfaces and a substrate sheet for higher production efficiency, as disclosed in U.S. Pat. No. 4,984,339 and of European Patent No. 0464753A1, metal mold discs and spacer plates are alternately piled up in a drum shape, then molten thermoplastic resin is extruded onto the surface of the drum while the drum is being rotated, thus pushing resin into the metal mold cavities to mold the hook surface fastener. Then, while molding hooks on the substrate sheet, the hooks in the cavities are pulled off the drum surface together with the substrate sheet in synchronism with the rotation of the drum. In the case of injection molding, the metal mold is opened first, then a molded product is ejected out of the mold by actuating the ejector pin provided inside the metal mold having the hook cavities.
Simultaneous molding of the hooks of the same shape and density onto both sides of the substrate sheet by the rotary drum injection molding as mentioned above, requires the process of pulling out the engaging elements in the cavities, molded on both sides of the substrate sheet off the drum surface in synchronism with the rotation of the drum. Since the engaging elements on both sides of the substrate sheet and the substrate sheet itself are not completely cooled down to be solidified, and since the resistance to the strength to pull the engaging elements out of the cavities is not necessarily the same on each side of the substrate sheet, the engaging elements on either one of the sides may come off first. This tends to cause vibration of the substrate sheet where it is pulled sometime damaging part of the surface fastener and obstructing smooth removal of the engaging elements.
On the other hand, in simultaneous molding of the hooks in the same shape and density onto either side of the substrate sheet by the injection molding, when the injection molding machine is opened to take out the molded product, the areas of both sides of the curtain connector contacting the mold are of the same size. Therefore, it is difficult to predetermine in which metal mold the curtain connector is left, so that it is necessary to provide ejector pins to take the connector out of the mold in both of the molds, thus causing higher production cost.